Palaeobatrachidae

Introduction

The †Palaeobatrachidae is an extinct group of frogs. They lived principally from the Eocene through Pliocene in Europe, but some fossils are known from the Cretaceous (see below). Like pipids, they were highly aquatic. Even the tadpoles are well preserved as fossils! Their tadpoles lacked beaks and denticles (Type 1 tadpoles). Palaeobatrachids resemble pipids in many other features, such as elongate finger and toe bones, greatly expanded ilia (hip bones), and elongate, nonpedicellate fanglike teeth. However the vertebrae of these frogs were procoelous (articulating concavity on the anterior end) rather than opisthocoelous (articulating concavity posterior) as in pipids, and some of the vertebrae in the hip region were fused to form a synsacrum. Some taxa are known to have an additional bony element in the fourth finger and fifth toe (Estes and Reig, 1973). Some palaeobatrachids reached a size of 120 mm snout-vent length.

Discussion of Phylogenetic Relationships

Ford and Cannatella (1993) defined †Palaeobatrachidae as commonly used: the node-based name for the most recent common ancestor of †Palaeobatrachus, †Neusibatrachus, †Pliobatrachus, †Albionbatrachus, and †Lithobatrachus, and all of its descendants. Estes and Reig (1973) allied †Palaeobatrachidae to the Pipidae, and Cannatella (1985) and Cannatella and de Sá (1993) explicitly listed synapomorphies supporting this relationship. Estes and Reig (1973) distinguished †Palaeobatrachidae from Pipidae in having procoelous vertebrae (apomorphic), a synsacrum (apomorphic), and the presence of mentomeckelian bones (plesiomorphic). †Palaeobatrachus occidentalis (Estes and Sanchíz, 1982) from the Cretaceous of North America is known only from ilia, so its inclusion in †Palaeobatrachidae is somewhat tentative. Likewise, the Jurassic-Cretaceous fossil †Neusibatrachus (Seiffert, 1972) is procoelous, but lacks a synsacrum and some other features found in the Tertiary fossils.

References

Cannatella, D. C. 1985. A phylogeny of primitive frogs (archaeobatrachians). Ph.D. Dissertation, The University of Kansas, Lawrence.

Cannatella, D. C., and R. O. de Sa. 1993. Xenopus laevis as a model organism. Syst. Biol. 42(4):476-507.

Estes, R., and O. A. Reig. 1973. The early fossil record of frogs: a review of the evidence. Pp. 11-63 In J. L. Vial (Ed.), Evolutionary Biology of the Anurans: Contemporary Research on Major Problems. University of Missouri Press, Columbia.

Estes, R., and B. Sanchiz. 1982. New discoglossid and palaeobatrachid frogs from the Late Cretaceous of Wyoming and Montana, and a review of other frogs from the Lance and Hell Creek Formations. J. Vert. Paleo. 2(1):9-20.

Ford, L. S., and D. C. Cannatella. 1993. The major clades of frogs. Herp. Monogr. 7:94-117.

Seiffert, J. 1972. Ein Vorläufer der Froschfamilien Palaeobatrachidae und Ranidae im Grenzbereich Jura-Kreide. Neues Jahrb. Geol. PalÉont. Monatshefte 1972:120-131.